Wave-powered vessels have been described in U.S. Pat. Nos. 7,371,136; 8,043,133; and published applications US 2008/188150 A1; US 2008/299843 A1; and WO/2008/109022. Exemplary vessels are manufactured and sold by Liquid Robotics, Inc., Sunnyvale Calif., USA under the brand Wave Glider®.
A previously unrelated field of development covers large stationary systems near shore that use wave motion to generate electrical power for communities on land. U.S. Pat. No. 4,134,023 discusses an apparatus for extracting energy from waves on water. U.S. Pat. No. 6,194,815 provides a piezoelectric rotary electrical energy generator. Published application US 2004/0217597 A1 discusses wave energy converters that use pressure differences. U.S. Pat. No. 3,928,967 is the so-called “Salter's Duck” patent, an apparatus and method of extracting wave energy. The status and perspectives of wave energy technology is generally reviewed by Clement et al. in Renewable and Sustainable Energy Reviews 6 (5): 405-431, 2002.